It is known in the art to use a waterproof liner (or “bootie”) as an insert in an article of footwear to protect a wearer's foot from water and to provide comfort and warmth to the wearer's foot. U.S. Pat. No. Re. 34,890 to Sacre, U.S. Pat. No. 5,499,459 to Tomaro, and U.S. Pat. No. 5,526,584 to Bleimhofer et al. describe such waterproof booties.
The composition of such waterproof booties varies. In some booties, the waterproof material defines a continuous barrier that surrounds a user's foot while in others the waterproof material is not continuous, allowing water to come into contact with a user's foot. Some booties are constructed of material that is vapor permeable/water impermeable while others are constructed of material that is both vapor and water impermeable.
The method of manufacturing such waterproof booties also varies. Some of the manufacturing processes used are labor intensive and time-consuming and some manufacturing processes do not result in a completely waterproof shoe construction. For example, in one method of making such a bootie, two fabric bootie side portions are stitched together to form a generally tubular shape. The tubular bootie is inserted within a shoe upper and the upper end of the bootie is secured to the shoe upper near the top edge of the upper, generally by stitching. A sole shaped board bottom is temporarily adhered to a shoe last by adhesive, tacks, or other suitable fasteners. The last with attached board bottom is placed within the bootie and shoemaking equipment is used to roll the lower edge of the bootie and shoe upper under the perimeter of the board bottom and secure them in position with cement. An outsole is then secured to the shoe upper and bootie using conventional methods. During this process, the waterproof lining may be damaged when rolling the lower edge of the bootie around the board bottom. If the excess material present at the lower edge of the bootie is not carefully eased into position when the bootie edge is rolled under the board bottom, folds or gaps also may result that allow faster penetration of water into the interior of the shoe.
Accordingly, there is a need in the art for a waterproof footwear liner that is easy to manufacture and that is produced using a process that has less of a potential to damage the waterproof lining of the bootie being produced.